<template>
  <div>
    <!-- 无id时, 可以使用index(反正也是就地更新) -->
    <div
      v-for="(item, index) in arr"
      :key="index"
      style="display: inline-block"
    >
      <input v-model="into" type="checkbox" />
      <span>{{ item }}</span>
    </div>
    <p>你选中的元素, 累加的值和为:{{ into(index) }}</p>
  </div>
</template>

<script>
export default {
  data() {
    return {
      arr: [9, 15, 19, 25, 29, 31, 48, 57, 62, 79, 87],
    };
  },
  computed: {
    into(index) {
      return this.arr.forEach((index) => (item += item));
    },
  },
};
</script>